Typically there are many shortcomings for traditional pipeline pumps: Almost all the pipeline pumps are shaped by casting, characterized with complicated structure of overflow part, cumbersome products and heavy consumption of materials. The hydraulic performance of the pumps is not desirable, and the pumps are working in part load with low efficiency. In addition, the casting process pollutes environment; for the overflow part of pipeline-type multi-stage centrifugal pump with small flow rate and high pumping head, it is difficult to cast due to the existence of the narrow and long overflow channels in many parts of the pump, such as the impeller and flow guide vane.
In view of that, the present invention is hereby proposed.